Improvement in hot-air furnaces



O. BELLMAN.

Hot-Air Furnace.

Patented Nov. 26,1872.

"Hull Imm M m N R w w V4 N, 0 c M w P 6 O m U m M A Wiizesses.

UNITED STATES OSCAR BELLMAN, OF HAGERSTOWN, MARYLAND, ASSIGNOR TOHIMSELF PATENT OFFICE.

AND WILLIAM BINKLEY, OF MIDDLEBURG, PENNSYLVANIA.

IMPROVEMENT IN HOT-AIR FURNACES.

Specification forming part of Letters Patent No. 133,293, dated November26, 1872; antedated November 25,

To all whom it may concern:

Be it known that I, OSCAR BELLMAN, of Hagerstown, Washington county,Maryland, have invented certain Improvements in Hot- Air'Furnaces, ofwhich the following is a specification:

In the accompanying drawing, Figure l is a perspective view of myimproved furnace. Fig. 2 is a vertical transverse section near the backof the furnace. Fig. 3 is a central vertical section from front to rearof the furnace. Fig. 4. is a detached view, showing the manner ofcasting the air-pipes in sections.

My invention consists, first, in a corrugated plate above the fire-pitfor the double purpose of increasing the heating-surface and preventingthe plate from warping and cracking,

by fire; second, in a secondary arch-plate above said corrugated platethird, in an elevated and inclined mouth-piece to the fire-pit whichacts as a heating-surface, and from its position and form is not liableto warp by fire; fourth, in the use of a single iron plate withoutfire-brick or other lining for the sides'of the fire-pit and as aradiating-surface for the hot-air chamber fifth, in the use of a seriesof cleaning-holes in connection with a series of air-tubes forming awinding and descending flue; seventh, the combination of a direct draftwith a series of air-tubes forming a double labyrinth or winding draft.

My invention or improvements herein described are intended to remedycertain defects which I have found in manufacturing a furnace for whicha patent was granted to myself and John W. Garver in 1870, and to whichreference is made for the general construction of the furnace.

In the accompanying drawing, A is the furnace proper, which is made ofcast-iron, and entirely inclosed in brick-work B. The arrows made infull line represent the course of the smoke, and the dotted arrowsshowthe direction of the air through the furnace. Above the fire-pit isa corrugated plate, 0, above which is a curved arch-plate, D. Thecorrugated plate gives an extraordinary extent of surface for radiationon the upper side, and

t the arch-plate D creates a strong current up through the space betweenthe two plates. This current very rapidly carries OK the heat from plate0, and thus keeps it from getting excessively hot; and the corrugationsso stilfas set forth.

on the plate that it is not liable to crack or warp like an ordinaryplate or arch. The mouth-piece E of the fire-pit is arched very highfrom the door to the corrugated plate 0, and affords a very extensiveheating-surface. Also, this large mouth-plate gives a roomy chamber fordiffusing the heat from the top of the fire over an extensive area ofiron plate, and thus relieves, in part, the hottest parts of thefire-pit. The mouth-plate forms a double arch, which resists the warpingaction of the fire. The side walls F of the fire-pitI propose to usewithout the usual fire-brick lining, in order that these walls maybetter'serve as heating-surfaces, and also to carry off the heat morerapidly, and thus prevent the fire from becoming too hot and scorchingthe air. By this plan the walls F are far less liable to burn out and.the furnace will last much longer.

In the rear of the furnace I have made a series of cleaning-holes, G, soas to reach and clean all the spaces between the air-tubes, where sootand ashes are liable to collect. Also, I have made two cleaning-holes,H, in the front plate, which are very convenient and also important tothe working of the furnace. At the rear of the fire-pit is adirect-draft hole, I, which will facilitate the kindling of the fire,and, therefore, is an improvement in connection with the winding fluesformed by the airtubes K. In connection with the walls F I may use avertical series of tubes, K, thus making these walls double, and formingahollow chamber or chambers, instead of having two tubes, K, in contactwith this wall.

My series of tubes may be cast in section, and then bolted together, asshown at L in Fig. 4, which is a great improvement over separate tubes,which require more labor.

Having described my invention, I claim 1. The abovedescribed arrangementand combination of the corrugated plate 0, the secondary plate D, andthe inclined and arched mouth-plate 'E, in relation to the fire-pit F,substantially as set forth.

2. I also claim the combination of the three series of hot-air tubes Kwith the cleaningholes G and direct-draft hole I, substantially OSCARBELLMAN. Witnesses:

DANIEL BREED,

EDM. F. BROWN.

